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Energy & Power

The Museum's collections on energy and power illuminate the role of fire, steam, wind, water, electricity, and the atom in the nation's history. The artifacts include wood-burning stoves, water turbines, and windmills, as well as steam, gas, and diesel engines. Oil-exploration and coal-mining equipment form part of these collections, along with a computer that controlled a power plant and even bubble chambers—a tool of physicists to study protons, electrons, and other charged particles.

A special strength of the collections lies in objects related to the history of electrical power, including generators, batteries, cables, transformers, and early photovoltaic cells. A group of Thomas Edison's earliest light bulbs are a precious treasure. Hundreds of other objects represent the innumerable uses of electricity, from streetlights and railway signals to microwave ovens and satellite equipment.

This is an experimental ruby laser made in 1963 at Ohio State University. Edward Damon, a researcher at the University’s Antenna Laboratory, made this and several other lasers during his investigation of Theodore Maiman’s successful ruby laser experiments of three years earlier.

An important part of science consists of replicating the experiments conducted by other researchers and confirming their results. Like Maiman's 1960 laser, Damon's 1963 laser used a photographer's helical flashlamp to energize the ruby crystal. It demonstrated the use of mirrors external to the ruby rod instead of mirrors deposited in the crystal itself. The mirrors are on adjustable mounts that allowed Damon to make a variety of experiments with this unit.

This is the discharge unit for the third type of laser invented. Dr. Ali Javan and his colleagues William Bennett and Donald Herriott demonstrated this laser at Bell Labs in December 1960. Using a mixture of helium and neon gasses, this laser emitted a continuous beam of light at 1.153 nano-meters, in the near-infrared part of the spectrum. Their successful demonstration proved crucial for many applications. The first supermarket scanners, made by Spectra Physics, used a helium-neon laser, as have many other commercial devices.

Ali Javan came to the U.S. from Iran in 1948 and trained in the laboratory of maser inventor Charles H. Townes at Columbia University. When he received his Ph.D. in 1954, Javan went to work at Bell Labs where began investigating the possibility of making a laser using a gaseous medium. His laser was the first gas laser as well as the first laser to produce a continuous beam of radiation.

This is one section of a laser amplifier tube from the Shiva experimental fusion apparatus, operated at Lawrence Livermore National Laboratory from 1978 through 1981. Scientists used the Shiva device to test theories about how lasers might be used to trigger a nuclear fusion reaction. The research program was part of the continuing quest to harness nuclear fusion as a source of energy.

Lasers are useful in this type of research since they emit a narrow beam of intense radiation. Shiva focused the energy of twenty laser beams on a tiny target of nuclear fuel to determine how the fuel would react. This amplifier tube is a short section of one of the twenty beam paths and contains panels made of neodymium glass that focus the light beam.

Scientists first made lasers using solid crystals or mixtures of gasses in 1960. Lasers using liquid dyes were developed in 1965. Dyes proved useful for making lasers that could be tuned over a range of light frequencies, somewhat similar to a musical instrument that can be tuned to different sound frequencies. Each of these five glass ampoules contains about 1 microgram of dye in a solution with 50 milliliters of ethyl alcohol. The glass ampoules are storage containers. In operation a dye is typically pumped through the laser apparatus.

These dye samples come from the Atomic Vapor Laser Isotope Separation Program (ALVIS) at Lawrence Berkeley National Laboratory. Light from a copper-vapor laser changed color (or frequency) by passing through a given dye, resulting in a laser beam with a specific frequency. Different frequencies equal different energy levels. Since atoms absorb energy at different frequencies, changing the laser light's color is a good way to impart just the right amount of energy needed to separate atoms such as isotopes that are almost, but not quite, identical.

A major breakthrough marks only the beginning of a scientist's work. In November 1960 Peter Sorokin and Mirek Stevenson, at IBM's Watson Research Center, successfully demonstrated a second type of laser. They energized a crystal of calcium-fluorine treated with a variety of uranium (written in chemical symbols as CaF2:U3+) to generate a pulse of laser light.

Sorokin and other colleagues experimented with many elements as they learned more about both pulsed and continuous-wave lasers. This crystal, from mid-1962, was the first one made of strontium, fluorine and samarium (SrF2:Sm2+) to successfully operate. Laser research was a very competitive field. Despite their efforts at IBM, Sorokin told museum staff that a team from Bell Labs, "made the first CW [continuous wave] solid-state laser using an ordinary crystal of CaF2:U3+. After that achievement we abandoned our CW efforts and went on to other topics." Those other topics included significant early work on generating laser beams using liquid dyes.

The term “home-made laser” almost seems a contradiction but that is not the case. This gas laser was built by high school student Stephen M. Fry in 1964, only four years after Ali Javan made the first gas laser at Bell Labs. Fry followed plans published in Scientific American's "The Amateur Scientist" column in September 1964, (page 227).

The glass tube is filled with helium and neon and, as the magazine reported, "seems to consist merely of a gas-discharge tube that looks much like the letter 'I' in a neon sign; at the ends of the tube are flat windows that face a pair of small mirrors. Yet when power is applied, the device emits as many as six separate beams of intense light."

The discharge tube is the only piece of this particular laser that remains. The flat windows (called "Brewster windows") are square instead of round, and the electrodes are parallel to the gas tube instead of perpendicular. Otherwise it resembles the drawings in the magazine. Fry later earned a Ph.D. in physics with a dissertation on lasers.

Potential military uses for lasers have attracted both government funding and popular interest. While laser ”ray guns” remain in the realm of science fiction, significant research has been conducted toward that goal. In the 1980s, tests of a deuterium-fluoride (or DF) chemical laser were conducted at the U.S. Army's Redstone Arsenal. A chemical reaction created the energy necessary to generate a laser beam. As this object shows, that beam can be quite powerful.

In 1985, the Army transferred this test target to the Smithsonian. The target consists of six steel plates, each about 2 mm thick, bolted together. A hole of decreasing diameter is burned through the target from front to back. Information provided with the target reported that a 130 kilowatt laser illuminated the target from a distance of 60 meters for 5 seconds.

As scientists and engineers came to better understand lasers, they developed a multitude of uses for this light source. The development of Compact Discs (CDs) and Digital Video Discs (DVDs) revolutionized the audio and video recording industries. Lasers are essential in making and playing both types of discs. Scientists refer to laser light as "highly coherent," meaning that the photons stay tightly focused rather than spreading out like the light from a flashlight. Coherent light can be focused on a very small spot. The pits on CDs and DVDs are microscopic.

This is the laser assembly from a Sony model D-5 "Discman" portable CD player. Donated in 1985, it shows how small lasers had become only 25 years after their invention. This object also shows the dramatic decrease in the amount of power needed to operate a laser. The power supply for Theodore Maiman's 1960 ruby laser is about 6 feet tall by 2 feet square and weights about 500 pounds. By contrast, the Sony "Discman" weighed less than 1 pound and operated on AA batteries.

Lasers have proven very useful in the construction industry. One example is this Spectra-Physics model 910 "LaserLevel" made in the early 1980s. In use, a construction worker attached the unit to a tripod and adjusted it so that it was nearly parallel to the ground. The level automatically completed the adjustment process when activated, and then emitted a beam of infrared light from a rotating head. The worker then moved to where-ever a measurement was needed and used a special laser detector to complete the task.

The "LaserLevel" self-adjusted if bumped slightly and completely shut off if bumped too much. The level operated automatically so it allowed one person to do work of two, resulting in cost savings since fewer assistants were needed.

This Spectra-Physics model 1077 "Level-Eye" laser light detector was made in the early 1980s. After setting-up a laser-emitter a construction worker could use this detector to take readings and check for level on a job site. The unit has both a visual display and an audible tone to tell the worker when the detector is centered on the signal. It has two accuracy settings, plus or minus 1/8 of an inch or 1/16 of an inch.